Feeding mechanism for box blank machines



Nov. 28, 1939.

FEEDING MEICIIANISMl FOR BOX BLANK MACHINES Filed June 22, 1939 I5 Sheets-Sheet l INVENTOR ffar 52193 BY WQ-A ATTO R N EYS Nov. 28, 1939. K. 'su-:G

FEEDING MECHANISM FOR BOX BLANK MACHINES Filed June 22, 1939 3 Sheets-Sheet 2 INVENTOR Karl 'eg ATTORNEYS Nov. 28, 1939. K. slr-:G

FEEDING MECHANISM FOR BOX BLANK MACHINES Filed June 22, 1939 3 Sheets-Sheet 3 :J m. u1 T- hm, u H- 0A mif, w

INVENTOR Karl S4293 Qu-1.7M A/a4 ATTORNEYS Patented Nov. 28, 1939 PATENT oFFIcE FEEDING MECHANISM FOR BOX BLANK MACHINES Karl Sieg, Philadelphia, Pa., assignor to Samuel M. Langston Co., a corporation of New Jer- Sey Application June 22, 1939, Serial No. 280,433

14 Claims.

This invention involves certain improvements in feeding mechanism for delivering comparatively stiff sheets, such for instance as corrugated boards, in succession from a stack or pile to mechanism for printing, scoring, slotting or otherwise operating upon the sheets.

In machines for making box blanks and feeding a separate sheet for every'revolution of the printing cylinder or slotting head, the maximum length of sheet that can be properlyy operated upon is substantially equal to the circumference of the head or cylinder operating on the sheet. If the length of the sheet exceeds to a limited extent the periphery of the operating head, it is necessary to feed one sheet foreach alternate revolution of the head or cylinder. In either case, the feeding device takes the sheet from the pile and advances it to the feed rolls at such a rate that the speed of the sheet at the instant the forward edge is gripped by the feed rollers should equal the peripheral speed of said rollers, so that there will be no bending of the sheet or mutilation of the edge.

One object of the present invention is to pro- 5 vide a power transmission mechanism of the general type above referred to,'having means for changing the frequency of the cycles of operation 'of the feeding mechanism, without changing the speed of said mechanism at the instant the forward edge of the advancing sheet is gripped by the feed rollers.

By means of this transmission mechanism, the frequency of the cycles of operation of the feeding mechanism can be changed at will to feed a sheet 5 for every revolution or every alternate revolution of the slotting head or printing cylinder,depending upon the length of the blank being fed. This change in frequency is also advantageous in those cases where there are heavy ink spreads, since a greater amount of ink is made available through the standard ink distributing rolls by virtue of the fact that ink is taken on at each revolution of the printing cylinder, but is applied to a sheet only every other revolution.

Various other objects, features and advantages of the invention will be apparent from the following particular description, and from an inspection of the accompanying drawings, in which:

J Fig. 1 is a diagrammatic side elevation of a printer slotter shown with one form of drive for the sheet feeding mechanism, embodying the present invention, A

Fig.. 2 is a diagrammatic side elevation show- 3 ing the feeding of sheets successively through the field of action of the operating head, with the power transmission mechanism set to feed one sheet per revolution of said head,

Fig. 3 is a diagrammatic side elevation showing the feeding of sheets through the field of action of the head, when the power transmission mechanism is set to feed one sheet for every two revolutions of said head,

Fig. 4 is a diagram showing the velocity of the feeding mechanism at different stroke positions, with the power transmission mechanism set to feed one sheet per revolution of the operating head,

Fig. 5 is a diagram showing the velocity of the 'feeding mechanism at different stroke positions,

with the power transmission mechanism set to feed one sheet for every two revolutions of the head,

Fig. 6 isa side elevation of the power transmission mechanism shown in Fig. 1, certain parts being broken away and certain parts being shown in section,

Fig. 7 is a section taken on line 1-1 of Fig. 6, but showing the speed change gearing of the power transmission mechanism in neutral position,

Fig. 8 is a top plan view of the transmission mechanism of Figs. 6 and 7, but on a smaller scale,

Fig. 9 is a diagrammatic view showing the position of certain gears of the transmission mechanism of Figs. 1, and 6 to 8, when the speed of the output shaft of said mechanism is at its maximum,

Fig. 10 is a View similar to Fig. 9, but showing the position of the same gears of the transmission mechanism after the input shaft 0f said mechanism has rotated one revolution from the position shown in Fig. 9, l

Figs. 11, 12 and 13 are horizontal sections, somewhat diagrammatically showing other forms of power transmission mechanisms which may be employed in carrying out the present invention, certain parts of said mechanisms being shown in top plan view,

Fig. 14 is a horizontal section through another form of power transmission mechanism which may be employed,

Fig. 15 is a section taken on line I5-l5 of Fig. 14,

Fig. 16 is a horizontal section through another form of power transmission mechanism which may be employed, and

Fig. 17 is a section taken on line ll-I'I of Fig. 16.

In the specific form of machineshown in Fig.

1, which has been selected for purposes of illustration, and to which the invention may be applied, there is provided the usual frame structure (not shown), which carries a feed table I0 upon which may be stacked a plurality of superpos'ed relatively stiff sheets between guide members II, and between a pair of brackets I2 and I3, one being disposed at the front end and the other at the rear. The rear bracket I3 is adjustable lengthwise of the table I0 in accordance with the length of the sheets to be fed, and the guides II laterally in accordance with the width of the sheets. There may be as many of these front and rear brackets I2 and I3 as may be desired depending upon the width of the sheets being fed.

The sheets are fed successively into the field of action of the machine by a feed mechanism, which includes a reciprocating bar I4, guided in a groove in the table l0, so as to move back and forth in the direction in which the sheets are to be fed. This bar I4 may be actuated by any suitable means, as for instance an oscillating lever I5, fixed to a rocker shaft I6, to which is affixed another lever I'I connected to a slide I8 on the feed bar I5 by means of a link 20. The lever I5 is connected to one end of a connecting rod 2l, the other end being operated by a power transmission mechanism, which embodies the present invention, and which will be hereinafter described.

The feed bar Il has one or more feeding members or knockers 23, rigidly connected thereto, but adjustable along the length thereof in accordance with the length of the sheets to be operated on. The feed knocker 2 3 has a shoulder member 24, positioned to engage the rear edge of the bottom sheet during its forward movement.. When the shoulder member Zl of the knockers reach a position rearwardly of the rear edge of the stacked sheets, the bottom sheet will drop, 'so that on the next forward stroke of the knocker 23, said shoulder member 2li will engage the rear edge of said lowermost sheet, and will move said sheet forwardly.

'Ihe feeding mechanism per se so far described forms no part of the present invention, and may be of any suitable form such as that shown in the Moritz Patent No, 1,797,692, the Sieg Patent No. 1,644,695, or the Langston Patent No.1,150,2l0. The details of this feed construction are therefore omitted for the sake of simplicity.

The feeding mechanism delivers the sheets successively to a suitable printer slotter, which in the form shown includes a rst pair of feed rolls 28 and 29, and two pairs of printing units separated by two pairs of feed rolls 30 and 3l. Each of these printing units includes a lower pressure cylinder 32, and an upper printing cylinder 33 carrying a type plate, which is inked by a series of ink fountain rolls (not shown). Different inks are supplied to the type plates of different printing cylinders, and the type plates and cylinders may be so positioned that, as the cylinders operate in succession, the two printings will be in the desired registry.

The sheets that have been printed pass through `a scorer 35, and then through a slotter, includof said head 31, to vary the distance therebej tween, and thus control the length of the unslotted portion of the blank between the ends of the slot extending in from opposite edges. The upper slotting head 3'I is of the same diameter as that of the upper printing cylinders 33.

All of the rotatable parts of the printer slotter which contact with the travelling sheets are op' erated at the same peripheral speed as the speed of the advancing sheets. A train of gears is shown in dot and dash lines, and receiving power from a drive shaft 40.

Fig. 2 shows two successive sheets A-and B advancing through the machine after the slots at the forward end of the sheet A have been completed, and while the slots at the other end are in the process of being formed, the sheet feeding power transmission mechanism being set to feed one sheet for every revolution of the slotting Vheads 31. With this setting of the transmission mechanism, each slotting head 31 carries twol knives 38, the peripheral distance X therebetween being equal to the length of the unslotted portions of the sheet, and the maximum length of sheet that can be operated upon will be equal to the circumference of said heads. When slot- A ting such maximum length sheets, the knives 38 will be close together substantially as shown in Fig. l, and the sheets will be fed close together almost in end to end contact.

As a feature of the present invention, a power transmission mechanism is provided for the sheet feeding, by means of which the total time cycle of the feeding-mechanism may be changed without changing the speed of travel of the sheets through the machine, to permit operations on longer sheets or to slow down the feeding of the sheets to permit heavy ink spreads thereon. For that purpose, the power transmission mechanism is constructed, so that irrespective of the time cycle of the feed mechanism, said feed mechanism will have a maximum speed'at the portion of its forward strokewhen the forward edge of the sheet being fed is first gripped between the first pair of feed rolls 28 and 29 as shown in Fig. 1. Since the forward edges of the stacked sheets are usually maintained at the same distance from these feed rolls 28 and 29, as determined by the position of the front bracket I2, regardless of the length of the sheets, this maximum speed must occur in the same position of the feed slide I8 shown in Fig. 1, irrespective of any changes in thetime cycle of said slide.

In Figs. 1, and 6 to l0 is shown one form of sheet feeding power transmission mechanism, which maybe used to accomplish this function, and which includes an input shaft 50 driven from the drive shaft 40 through intermeshing spur gears 5I and 52, and at the same angular speed as that of the printing cylinders 33 and the slotting heads` 31, so that said cylinders and said heads will rotate one revolution for every revolution of the input shaft 50.

The mechanism also includes an output shaft 53, parallel to the input shaft 50,. and a rst variable speed ratio unit between said shafts, shown as a pair of intermeshing elliptical gears 54 and 55, having their major'and minor radii in the ratio of 2:1. With this transmission means, while the input shaft 50, printing cylinders 33 and slotting heads 31 rotate through one revolution at a constant speed, the output shaft 53 will rotate through one revolution but at a variable speed, and .will have a given maximum angular velocity at the phase or portion of the cycle sh'own in Figs. 1, 7 and 9.

Aiiixed to the output shaft 53 is a crank 56, which is connected to one end of the connecting rod 2I of the feeding mechanism in such angular position, that when said output shaft is at its maximum velocity phase shown in Figs. 1, 7 and 9, the feed slide I8 Will be traveling at a maximum velocity equal to the peripheral velocity of the feed rolls 28 and 29, and will be in that position of its forward stroke at which the forward end' of the sheet being fed is at the nip portion of said feed rolls. During the remainder of the forward stroke of the feed slide I8, the feeding of this sheet through the machine will be accomplished by the rotating feed parts of said machine.

Since the feed slide I8 will effect a complete stroke for every revolution of the output shaft 53. and since said shaft rotates at the same frequency or at the same total time cycle as that of the printing cylinders 33 and slotting heads 31, the feeding mechanism will fee-d one sheet per revolution of saidcylinders and said heads.

A speed change gearing is provided for changing the total time cycle of the feeding mechanism with respect to the printing cylinders and I slotting heads. In the. form shown, this gearing includes a pair of intermeshing circular reduction spur gears 51 and 58, in series with elliptical gears 54 and 55, and having a 211 speed ratio. These gears 51 and 58 if used alone would reducethe maximum speed of the output shaft 53 one-half at the phase thereof shown in Fig. 9, if'no compensating means be provided.

In order to neutralize the effect of the reduction gears 51 and 58 on the maximum speed of the output shaft 53, there is provided a second variable speed ratio unit shown as a pair of intermeshing elliptical gears 60 and 6I in series with the first pair of elliptical gears 54 and 55, and having their major and minor radii in the ratio of 2:1. When the drive is through both pairs of lelliptical gears and the reduction gears 51 and 58, the output shaft 53 will be driven at one-half the frequency or total time cycle of the input shaft However, the pair of elliptical gears 60 and 6I is arranged to correspond in position with the elliptical gears 54 and 55 in the portion of the cycle shown in Fig. 9, so that the maximum velocity of the output shaft 53 will be the same in this portion regardless of the setting of the speed change gearing.

The elliptical gear 54 is fixed to the shaft 50,

while the elliptical gear 55 is so mounted that4 it can be coupled to or uncoupled from the output shaft 53. The smaller speed change gear 51 is rigid with the `ellipticaLgear 55 and a sleeve 62, and encircles the output shaft 53. The larger speed change gear 58 encircles the shaft 50, and is rigid with a sleeve 63 and the elliptical gear 60. The other elliptical gear 6I encircles the shaft 53.

The means for connecting the two shafts 58 and 53 through either the first or the second transmission -means includes a sleeve 64 keyed on the shaft 53, and adapted to interlock with teeth 66 on the sleeve 62 or teeth 61 on the elliptical gear 6I.

' When the clutch sleeve 64 engages the clutch teeth 66, the power is transmitted from the shaft 50 to the shaft. 53 through the elliptical gears 54 and 55.and,the clutch. When the clutch sleeve 64 engages the other clutch teeth 61, the power is transmitted from the shaft 50 to the shaft 53 through the gears 54, 55, sleeve 62.

gears 51, 58, sleeve 63, gears 60 and 6I, and the clutch.

The axial shifting of the sleeve 64 into the desired speed change setting may be accomplished by any suitable means. As shown, there is employed a handle 10, connected to a pivot shaft 1I, journalled on a frame plate 12 on the upper side of the transmission housing 13. Fixed to this pivot shaft' 1I is a bracket or arm 14 carrying a yoke 15, extending in a peripheralgroove 16 of the sleeve 64. Connected to one end of the handle is a spring-pressed locking pin 11, adapted to extend into either one of two holes 18 to determine the extreme axial positions `of the sleeve 64 in coupling engagement with the clutch teeth 66 or 61, and to hold said sleeve in either of said positions.

When the power transmission mechanism is in position shown in Fig. 9 with the major axes of the rst pair of elliptical gears 54 and 55 in' alignment, the second pair of elliptical gears 60 and 6I will be in corresponding position, regardless of whether or not the first or the second transmission means is coupled between the two shafts 5D and 53. In this position of the elliptical gears, the feedslide I8 will travel at maximum velocity in the position of its forward stroke shown in Fig. 1.l In any other position of the feed slide I8, the angular position of the first pair of elliptical gears 54 and 55 will depend upon whether or not one or the other of the power transmission means is coupled between the two shafts 50 and 53. It is therefore essential, in order to maintain a predetermined relationship between the position of the feed slide 85 I8 and the angular position of the elliptical gears, that the gear shifting be effected when the feed slide I8 is in the same predetermined position', for instance -that shown in Figs. 1, 6, 7 land 9. For indicating this predetermined stopping position for the transmission mechanism, there may be employed flange plates 80, secured to the ends of the shafts 50 and 53 respectively for rotation'therewith,l and carrying indication marks 8I on their peripheries cooperating with pointers 82 secured to the housing 13. The indication marks 8| are so positioned, that when both of them are in registry with their respective pointers 82, both pairs of elliptical gears will be in the same phase shown in Fig. 9, and the crank 56 will be in the maximum velocity position shown in Fig. 1.

In the operationv of the mechanism, when the coupling sleeve 64 is in engagement with the Aclutch teeth 66 for a 1:1 frequency transmission,

the output 4shaft 53 will be driven at a variable speed and the feed slide I8v will be driven at a variable speed as indicated by the curve in Fig. 4. In this curve, the ordinates D indicate the linear speed of the feed slide I8, at a corresponding .stroke position, and the interval between said ordinates represents i of a revolution of the input shaft 50, printing cylinder 33, and slotting heads 31, so that the curve indicates the speed of the feed slide I8 at any position of its stroke, and the corresponding phase .position of said printing cylinders and said slotting heads. The ordinate D corresponds to the position shown in Fig. 1, at which the feed slide I8 will reach its maximumvelocity, equal to the peripheral velocity of the feed rolls, in which position the forward edge of the sheet will be substantially at the nip portion of the feed rolls 28 and 29.

When the coupling sleeve 64 is in engagement with-the clutch teeth 61, the drive will be through the second transmission, and the shaft 53 will be driven at a variable speed to make one revolution for every two revolutions of the input shaft 50. When the elliptical gears 54- and 55 reach the position shown in Fig. 9, the second pair of e1- liptical gears will be in corresponding position, so that the angular velocity of the output shaft 53 in this phase position of the gears will be the same as it was when driving through the rst transmission means. At the end of one revolution of the input shaft 50, the elliptical gears 54 and-55 will be in the position shown in Figs. 9 and 10, while the elliptical gears 60 and 6| will be in exactly the reverse position as shown in Fig. 10, so that the speed of the output shaft 53 will be materially less than that in the 1:1 setting of the speed change gearing. At the end of the second revolution of the input shaft 53, the two sets of elliptical gears will again be in the position shown in Fig. 9, and the output shaft 53 will then again reach the same maximum velocity attained by the transmission in the 1:1 gear setting.

In Fig. 5 is shown a curve, which is similar to the curve of Fig. 4, except that it applies to the 1:2 transmission, and which indicates that the feed slide I8 makes one complete stroke' for every two revolutions of the input shaft 50, and the maximum velocity D of the feed slide i8 occurs in the same position of its forward stroke, and is equal to the maximum velocity attained by the feed slide when running on a 1:1 speed ratio. Thus there will be one point in the cycle of movement of the feed slide l0, where the maximum linear velocity will be the same irrespective of whether the clutch be in one position or the other. In one case, this point is reached once in each revolution of the printing cylinders 33 or the slotting heads 3ft, and in the other case, it is reached once in each two revolutions of these members.

With the feed of one sheet in every two revotions of the printing cylinders and slotting heads,

a sheet longer than the circumference of said members can be properly operated on. In Fig. 3 is shown the operation of the slotting head pn successive sheets A' and B with a 1:2 setting of the speed change gearing. With this setting, one of the knives 38 is removed, so that the same knife 38 operates to' form the slots on both ends of each sheet, and the maximum length of the sheets that can be operated on is equal to the circumference of the slotting head plus the circumferential length of the knife.

Instead of using elliptical gears, any other equivalent means may be employed for imparting variable angular velocity to the output shaft, and for maintaining the same linear velocity of the feed mechanism at a portion of the cycle thereof irrespective of changes in its ltotal time cycle. For instance, I may employ for that purpose other shapes of non-circular gears, eccentric slide cranks, Geneva gears, or the like.

Fig. 11 shows another form of sheet feeding power transmission', comprising the input shaft 50, driven from the drive shaft 40 by suitable gearings as in the construction of Figs. 1 to 10, to rotate said input shaft at the same constant angular speed as that of the slotting heads, and two parallel output shafts 53a and 53D, each carrying a crank 56 for selectively operating a connecting rod 2| to the reciprocating feed mechanism. Between shafts 50 and 53a is a rst Variable speed ratio unit in the form of `an eccentric slide. crank, comprising a slotted crank disc 90,

fixed to the end of the input shaft 50, and a crank v justable eccentric slide crank,

arm 9| xed to the opposed end of the shaft 53a, and carrying a. crank wrist roller 92, slidable in the slot of said disc.

Parallel to the output shaft 53a is a shaft 93, driven from said output shaft by intermeshing reduction spur gears 94 and 95, having a speed -ratio of 2:1, so that said shaft 93 will rotate onehalf revolution for every revolution of said output shaft. Between the shafts 93 and 53h is a second variable speed ratio unit in the form of an eccentric slide crank, comprising a slotted disc 96 fixed for rotation with the gear 95, and a crank arm 91 fixed to the end of the shaft 53h, and having a crank wrist roller connection in the slot of said disc.

-The first slide crank 90, 9| has a suitable speed ratio at the maximum velocity phase of the crank arm 9|, to impart the desired maximum angular velocity to the output shaft 53a and in turn to thevreciprocating feed mechanism. A suitable speed ratio between the inlet and outlet side of this iirst slide crank in this maximum velocity phase may be 1 to 1.76, and of the second slide crank 96, 9'! in this phase 1 to 2 to neutralize the effect of the reduction gears 94 and 95. The two output shafts 53a and 531) will therefore rotate at the same maximum angular speed at the same portion of their cycle, but shaft 53h will rotate one-half revolution at variable speed for every one revolution of the input shaft 50, while output shaft 53a will rotate one revolution at variable speed for every one revolution of said input shaft.

The feed'mechanism is therefore coupled selectively to either one of the output shafts 53a. or 53h by a connecting rod according to the desired total time cycle of said feed mechanism, the maximum speed of said feed mechanism at the portion of its stroke shown in Fig. l being the same with. either connection.

Fig. l2 shows another form of sheet feeding transmission mechanism, comprising the input shaft 50, output shaft 53, and three shafts |00, |0| and |02 parallel to said input and output shafts. Between the two shafts 50 and |00 is a speed change gearing including two pairs of intermeshing gears, one pair comprising gears |03 and |04 in a 1 to 1 speed ratio, the other pair comprising gears |05 and |06 having a 2 to 1 speed ratio. The gears |03 and |05 are fixed to t'ne input shaft 50, while gears |04 and |06 are loosely mounted on the shaft |00, but selectively coupled thereto byI a slidable clutch |01.

Between the two shafts |00 and |0| is a rst variable speed ratio unit in the form of an adcomprising a slotted crank disc |08 xed to the end of the shaft, and a crank arm ||0 xed to the opposed end of the shaft |0|, and carrying a crank wrist roller slidable in the slot of said disc.

Between the two shafts |0| and |02 is a spur gear transmission ||2 and ||3 with a 1 to 1 speed ratio, and between the two shafts |02 and 53 is a second variable speed ratio unit in the form of an adjustable eccentric slide crank, comprising a slotted crank disc ||4 on shaft |02, and crank arm I5 on the other shaft 53 with slidable crank -wrist connections to said disc.

The eccentricity of the two crank connections is adjustable according to the desired total time cycle of said mechanism, and desirably by a single adjusting mechanism, which does not interfere with the transmission between the two shafts |0| and |02. For that purpose, these shafts are journalled in a crank bearing block I6, movable by an adjusting screw ||1. The eccentricity of these two crank units can be adjusted simultaneously to a minimum extent, to impart the desired maximum angular velocity to the output shaft 53 for a 1 to 1 drive through the power transmission, or adjusted to a maximum extent to impart the same maximum angular velocity to said shaft in the same phase for a 1 to 2 drive. For instance, when it is desired to feed one sheet for every revolution of the slotting heads 31, the clutch |01 is shifted to couple the gears |04 to the shaft |00, and the eccentricityv of thetwo crank units adjusted to a minimum extent by the adjustment `of the block |I6, so that the speed ratio of each crank unit at maximum velocity phase of the output shaft 53 will be 1 to 1.32. With this 1 to 1 setting of the speed change gearing, the drive to the output shaft 53 will be through the gears |03 and |04, the first crank unit |08 and ||0, gears ||2 and ||3, and through the second crank unit 4 and ||5, and the speed ratio between input shaft 50 and output shaft 53 in maximum velocity phase of said i latter shaft will be 1 to 1.76.

When it is desired to feed one sheet for every two revolutions of the slotting heads, the clutch |01 is shifted to couple the gear |06 to the shaft |00, and the eccentricity of the two crank units adjusted to a maximum extent indicated approximately by the position F in dotted lines, so that the speed ratio of each crank unit will be 1 to 1.87. With this setting of the speed change gearing, the drive to the output shaft 53 will be through the gears |05, |06 at a 1 to 2 speed ratio, through the first crank unit |08, ||0, gears H2, 3, and through the second crank unit ||4, ||5, and the speed ratio between the input shaft 50 and the output shaft 53 in maximum velocity phase of the latter shaft will be 1 to 1.76, this being equal to the speed ratio with a 1 to 1 drive. This maximum velocity of the output shaft will occur in the same portion of its cycle in both settings of the speed change gearing.

The eccentric adjustment of the crank units between the two extremes indicated does not in any way affect the length of the connection between the output shaft 53 and the feed lever I5.

Fig. 12 is diagrammatic, and not intended to show the actual position and phases of the slide crank units with' respect to connecting rod 2|. For instance, in actual construction, the adjusting screw ||1 extends substantially vertically, and when the driving'and driven elements of each slide crank unit are in phase for maximum speed ratio therebetween, the crank 56 extends downwardly. It should alsobe noted, that the bearing block for shaft 53 is stationary, and therefore any adjustment of bearing block ||6 through screw ||1 will not affect the length of the connecting rod 2|.

Fig.' 13 shows diagrammatically another form of sheet feeding power transmission comprising the input shaft 50, output shaft 53, and an intermediate shaft |00, and a speed change gearing between shafts 50and |00 similar to that of I. Fig. 12.

it is `desired to feed one sheet per1 revolution of the slotting heads 31, the clutch |01 is moved in position to couple the gear |04 to the shaft |00, and the crank unit is adjusted to obtain the ratio of 1 to 1.76 above referred to at the maximum velocity phase of said latter shaft.

When it is desired to feed one sheet for every two revolutions of the slotting head, the clutch is moved in an opposite direction to couple the gear |06 to the shaft |00, and the crank unit is adjusted to obtain a ratio of 1 to 3.52 in the maximum velocity phase of the output shaft, so that the velocity of said output shaft at that phase will be the same as it was with a 1 to 1 setting.

Figs. 14 and 15 show another form of sheet feeding mechanism comprising input shaft 50, output shaft 53, and a pair of intermediate shafts |30 and |3| parallel to said shafts 50 and 53. Fixed to the shaft 50 is a gear |32, meshing with a gear |33 fixed to the shaft 30, the speed ratio between said gears being 4 to 1. Between the shaft 53 and the gear |33 is a speed change gearing, including two pairs of intermeshing gears, one pair comprising gears |34 and |35 in 4 to 1 speed ratio, and the other pair comprising gears v|36 and |31 also in the 4 to 1 speed ratio. 'I'he gears |35 and |31 are fixed to the shaft I3 I, while gears |34 and |36 are loosely mounted on shaft 53, and selectively coupled thereto by a slidable clutch |38. Between the two shafts |30 and |3| are two Geneva gear units, forming part of the speed change gearing. One of these Geneva gear units comprises cross gear |40, mounted on the inner face of the gear 35 for rotation therewith, and driven from four driving pins |4|, aixed to one side of the gear |33 in quadrant relationship. Also on this side of the gear 33 is the usual locking member |42 for cooperation with the cross gear |40. The other Geneva gear unit comprises cross gear |43, similar to gear |40, and mounted on the inner face of the gear |31 for rotation therewith, said gear |43 being driven from two driving pins |44 extending from the other side of gear 33, and diametrically arranged in respective alignment with two of the pins |4|. On one side of the gear |33 is the usual locking member for cooperation with the cross gear |43.

When it is desired to feed one sheet for every revolution of the slotting heads, the clutch |38 is moved into position to lock the gear |34 to the output shaft 53. With this setting of the speed change gearing, the transmission between the input and output shafts will be through gears |32 and |33, pins |4|, cross gear |40, and gears |35 and |34. Since there are four `driving pins |4'| cooperating with this cross gear |40, said pins `will cause the gear |34 to' rotate through four identical revolutions, each at varying speed for each turn of the gear |35, so that the output shaft 53 will rotate one revolution at varying speed for every revolution of the input shaft 50 at constant speed.

When it is desired to feed one sheet for every two revolutions of the slotting head, the clutch member |33 is moved into position to lock the gear 36 to the output shaft 53. With this setting of the speed change gearing,'the transmission will be through the gears |32 and |33, pins |44, cross gear |43, and gears |31 and |36. Since this Geneva unit has two driving pins |44, said pins will cause rotation of the gear |36 through pins. During the second quarter revolution 01'-- this gear |33, the gear |36 will be held stationary. During the third quarter revolution, the gear |36 will again rotate through a varying speed cycle, and during the fourth revolution, this gear will again be held stationary.

With either speed change setting, the cycles of operation of the reciprocating feed mechanism will be the same. In one setting however, the cycles of operation of said feed mechanism repeat themselves in correspondence with the repeatedrevolutions of the slotting head, while in the other setting, the feed mechanism is stationary during alternate revolutions of said head.

Figs. 16 and 17 show another form of sheet feeding transmission, in which the speed change gearing may be set to hold the reciprocating :feed mechanism stationary during alternate revolutions of the slotting head. This transmission includes input shaft 50, output shaft 53, a third shaft |50 parallel to said shafts 50 and 53, and a gearing between the shafts 53 and |50 for changing the frequency of operation of said shaft 53. This gearing includes two pairs of intermeshing gears, one pair comprising standard spur gears |5| and |52 having a 1 to 2 speed ratio, the other pair comprising a mutilated spur gear |53 and a spur gear |54, said latter gears having a 1 to 2 speed ratio between intermeshing parts thereof, and said gear |54 having a portion |51 with teeth omitted, to lock said gear |54 against rotation in predetermined rotative position when not meshing with gear |53, and to assure proper intermeshing of said gears |53 and |54 at the beginning of the intermeshing phase. 'I'he gears |5| and |53 are affixed to the shaft |50, while gears |52 and |54 are loose on shaft 50, but selectively coupled thereto by a slide clutch |55. The shaft |50 is driven from the shaft 50 through a gear |56 meshing with the gear |5|, the speed ratio between said gears being 2 to 1.

The teeth on the mutilated gear |53 extend substantially along one-half of the periphery thereof, and are shown in Fig. 17 on the upper half of saidgear.

For a feed of one sheet for every revolution of the slotting heads 31, the drive will be through gears |56, |5|, and |52 to the output shaft 53. For a feed of one sheet for every two revolutions of the slotting head, the drive will be through gears |56, |5|, shaft |50, mutilated gear |53 and gear |54. In both settings of the transmission, the output shaft 53 will rotate at the same speed. However, with a 1 to 2 feed, during the time the teeth parts of the two gears |53 and |54 are intermeshed, the gear |54 makes one complete revolution, and during the remainder of the revolution of said gear |53, the gear |54 is stationary.

In the construction shown in Figs. 16 and 17, there is no variable speed ratio unit, sothat variations in speed of the feed mechanism during its cycle are attained only through the crank and rod connections 56 and 2|. This is not entirely satisfactory, since it would be necessary to increase the length of the crank, and therefore the length of the stroke of feed bar |4 (see Fig. 1), to obtain the same feeding velocity as with an elliptical gear drive or its equivalent. A shorter stroke allows for ashorter minimum sheet length to be fed into the machine. It is desirable therefore to provide a variable speed ratio unit to attain the desired rate of variation in the speed of the feed mechanism during each of its cycles. In the construction of Figs. v1 to 15, this desired variation is cbtained through elliptical gears,

variable throw cranks or Geneva movements as already described. In the construction of Figs. 16 and 17, such a variable ratio speed unit preferably in the form of elliptical gears may be provided at the inlet side of the input shaft 50.

In all of the forms of construction shown, there is provided a power transmission mechanism with a speed change gearing for changing the frequency of operation of the reciprocating feed parts, without changing the speed of said parts at a definite portion of their cycle.

In the constructions of Figs. 1 to 13, this change in frequency is obtained by changing the total time cycle of the feeding mechanism, so that it takes two revolutions of the slotting head to complete one stroke of the feeding mechanism.

In the constructions of Figs. 14 to 1'7 however, the change in frequency is obtained by holding the feeding mechanism stationary during alternate revolutions of the slotting head,A the cycles of each stroke for both settings of the speed change gearing being identical.

As many changes could be made in the above construction, and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intendedthat all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A machine for making box blanks, including a reciprocable feeding mechanism for feeding stiff sheets successively from a stack, and a power transmission mechanism for operating said feeding mechanism, including means for changing the frequency of operation of said feeding mechanism, and means for maintaining the speed of said feeding mechanism in a given portion of its cycle substantially the same regardless of changes in said frequency.

2. In a machine for making box blanks wherein there is provided a rotatable member for op- I erating on sheets of stiff material, and a reciprocable feeding mechanism for feeding sheets successively from a stack, a power transmission mechanism for operating said feeding mechanism, including an input shaft, an output shaft, means connecting said output shaft and said feeding mechanism for operating said feeding mechanism, a speed change gearing for changing the frequency of operation of said output shaft with respect to said input shaft to change the frequency of operation of said feeding mechanism, and means for maintaining the speed of said feeding mechanism in a given portion of its cycle substantially the same regardless of changes in said frequency.

3. A machine for making box blanks from sheets of stiff material, having a slotting head, a pair of feed rolls, a reciprocable feeding mechanism for Afeeding sheets successively from a stack to said feed rolls, and a power transmission mechanism for operating said feeding mechanism, including means for changing the frequency of operation of said feedingmechanism, and means for maintaining the speed of said feeding mechanism, in that portion of its forward stroke at which the forward edge of the sheet being fed is substantially in the nip portion of said feed rolls, substantially equal to the peripheral speed of said feed rolls, regardless of changes in said frequency.

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4. A machine for making box blanks from sheets of stiff material, including a rotatable member for operating on said sheets, a reciprocable feeding mechanism for feeding said sheets successively from a stack, a power transmission mechanism for operating said feeding mechanism, including a speed change gearing for changing the frequency `of operation of said feeding mechanism, so that said latter mechanism will effect a complete feeding cycle for every one or two revolutions of said member according to the setting of said speed change gearing, and means for maintaining the speed of said speed change mechanism in a given portion of its cycle the same with either setting of the speed change gearing.

5. In a machine for making box blanks from sheets of stiff material, including a slotting head for operating on said sheets, a pair of feed rolls, a reciprocable feeding mechanism for feeding said sheets successively from a stack to said feed rolls, a power transmission mechanism for operating said feeding mechanism, including a speed change gearing for changing the frequency of operation of said feeding mechanism, to operate thro-ugh one cycle for every revolution of said slotting head or for every two revolutions of said slotting head, according to the setting of said speed change gearing, and means for maintaining the speed of said feeding mechanism, in that portion of its cycle wherein the forward edge of said sheet being fed is substantially in the nip portion of the feed rolls, the same and equal to the peripheral speed of said feed rolls with either setting of the speed change gearing.

6. A machine for printing and slotting sheets of stiff material to make box blanks, including a reciprocable feedingmechanism for feeding the sheets successively from a stack, a power transmission mechanism for operating said feeding mechanism, including an input shaft, an output shaft, a first transmission means between said shafts for driving said output shaft at a given frequency and at a given angular velocity at a portion of its cycle, a second transmission means between said shafts for driving said output shaft with a different frequency, but at the same angular speed at said portion of its cycle, means for coupling either one of said transmission means for drive operation between said shafts, -and means between said output shaft and said feed mechanism for reciprocating said feeding mechanism from said output shaft.

7. A machine for making box blanks, including a reciprocable feeding mechanism for feeding sheets successively from a stack, a power transmission mechanism for operating said feeding mechanism, including an input shaft, an output shaft, a first transmission means between said shafts for driving said output shaft ata variable speed and at a given frequency, a second transmission means between said shafts for driving said driven shaft at a variable velocity and with a different frequency, means for coupling either one of said transmission means for drive operation between said shafts, and connecting means between said output shaft and said feed mechanism for reciprocating said feed mechanism.

8. A machine for making box blanks, including a slottinghead for operating on sheets of stiff material to form said box blanks, a pair of feed rolls, and a reciprocable feeding mechanism for feeding sheets successively from a stack to'said feed rolls, a power transmission mechanism for operating said feeding mechanism, including means for reciprocating said feeding mechanism at a variable speed, and at a maximum speed at the phase of its forward stroke when the forward edger of the sheet being fed is substantially at the nip portion of said feed rolls, said maximum speed being substantially equal to th-e peripheral speed of said feed rolls,v and means for changing the frequency of operation of said feeding mechanism without changing the maximum speed of said mechanism at said portion of its forward stroke.

9. A machine for making box blanks, including a rotatable member for operating on stiff sheets to make said blanks, a reciprocable feeding mechanism for feeding sheets successively from a stack, a power transmission mechanism for operating said feeding mechanism, including means for changing the total time cycle of operation of said feeding mechanism, and means for maintaining the speed of said feeding mechanism in a given portion of its cycle the same, regardless of changes in said frequency.

10. A machine for making box blanks, including a slotting head for operating on stiff sheets to make said box blanks, a pair of feed rolls, and a feeding mechanism for feeding said sheets suclcessively from a stack towards said feed rolls, a

power transmission mechanism for operating said feeding mechanism, including a speed change gearing for changing the total time cycle of operation of said feeding mechanism, so that the period of each stroke thereof is equal to or twice the period of revolution of said slotting head, in accordance with the setting of said speed change gearing, and means for maintaining the speed of said feeding mechanism, in that portion of its cycle wherein the forward edge of the sheet being fed is substantially in the nip portion of the feed rolls, the same with either setting of said speed change gearing.

11. A machine for making box blanks, including a slotting head for operating on stiff sheets to make said box blanks, a pair of feed rolls, and a feeding mechanism for feeding said sheets successively from a stack towards said feed rolls, and a power transmission mechanism for operating said feeding mechanism, including a speed change gearing for changing the total time cycle of operation of said feeding mechanism, so that the period of each stroke thereof is equal to or twice the period of revolution of said slotting head, in accordance with the setting of said speed change gearing.

12. A machine for vmaking box blanks from sheets of stiff material,including a rotatable member for operating on said sheets, a reciprocable feeding mechanism for feeding said sheets successively from a stack, a vpower transmission mechanism for operating said feeding mechanism, includingl means for operating said feeding mechanism selectively through recurrent cycles at a given frequency, 'or intermittently through similar cycles at a less frequency, and means for maintaining the speed of said feeding mechanism in a given portion of its cycle the same regardless of changes inA said frequency.

13. A printer slotter for making box blanks, including feed rolls, a printing cylinder, a slotting head, a knocker feed for delivering the sheets from a stack to said feed rolls, a drive shaft for operating vsaid feed rolls, printing cylinder, and slotting head with the same peripheral speed, and connections between said shaft and said knocker feed, and selectively operable to deliver a sheet fer each revolution or each alternate revolution of said cylinder head.

14. A printer slotter for making box blanks, including feed rolls, a printing cylinder, a slotting head, a knocker feed for delivering the sheets from a stack to said feed rlls, a drive shaft for operating said feed rolls, printing cylinder, and slotting head with thesame peripheral speed, and 

